Life expectancy associated with different ages at diagnosis of type 2 diabetes in high-income countries: 23 million person-years of observation

BACKGROUND

The prevalence of type 2 diabetes is increasing rapidly, particularly among younger age groups. Estimates suggest that people with diabetes die, on average, 6 years earlier than people without diabetes. We aimed to provide reliable estimates of the associations between age at diagnosis of diabetes and all-cause mortality, cause-specific mortality, and reductions in life expectancy.

METHODS

For this observational study, we conducted a combined analysis of individual-participant data from 19 high-income countries using two large-scale data sources: the Emerging Risk Factors Collaboration (96 cohorts, median baseline years 1961-2007, median latest follow-up years 1980-2013) and the UK Biobank (median baseline year 2006, median latest follow-up year 2020). We calculated age-adjusted and sex-adjusted hazard ratios (HRs) for all-cause mortality according to age at diagnosis of diabetes using data from 1 515 718 participants, in whom deaths were recorded during 23·1 million person-years of follow-up. We estimated cumulative survival by applying age-specific HRs to age-specific death rates from 2015 for the USA and the EU.

FINDINGS

For participants with diabetes, we observed a linear dose-response association between earlier age at diagnosis and higher risk of all-cause mortality compared with participants without diabetes. HRs were 2·69 (95% CI 2·43-2·97) when diagnosed at 30-39 years, 2·26 (2·08-2·45) at 40-49 years, 1·84 (1·72-1·97) at 50-59 years, 1·57 (1·47-1·67) at 60-69 years, and 1·39 (1·29-1·51) at 70 years and older. HRs per decade of earlier diagnosis were similar for men and women. Using death rates from the USA, a 50-year-old individual with diabetes died on average 14 years earlier when diagnosed aged 30 years, 10 years earlier when diagnosed aged 40 years, or 6 years earlier when diagnosed aged 50 years than an individual without diabetes. Using EU death rates, the corresponding estimates were 13, 9, or 5 years earlier.

INTERPRETATION

Every decade of earlier diagnosis of diabetes was associated with about 3-4 years of lower life expectancy, highlighting the need to develop and implement interventions that prevent or delay the onset of diabetes and to intensify the treatment of risk factors among young adults diagnosed with diabetes.

FUNDING

British Heart Foundation, Medical Research Council, National Institute for Health and Care Research, and Health Data Research UK.

HbA1c levels in non-diabetic older adults - No J-shaped associations with primary cardiovascular events, cardiovascular and all-cause mortality after adjustment for confounders in a meta-analysis of individual participant data from six cohort studies

BACKGROUND

To determine the shape of the associations of HbA1c with mortality and cardiovascular outcomes in non-diabetic individuals and explore potential explanations.

METHODS

The associations of HbA1c with all-cause mortality, cardiovascular mortality and primary cardiovascular events (myocardial infarction or stroke) were assessed in non-diabetic subjects ≥50 years from six population-based cohort studies from Europe and the USA and meta-analyzed. Very low, low, intermediate and increased HbA1c were defined as <5.0, 5.0 to <5.5, 5.5 to <6.0 and 6.0 to <6.5% (equals <31, 31 to <37, 37 to <42 and 42 to <48 mmol/mol), respectively, and low HbA1c was used as reference in Cox proportional hazards models.

RESULTS

Overall, 6,769 of 28,681 study participants died during a mean follow-up of 10.7 years, of whom 2,648 died of cardiovascular disease. Furthermore, 2,493 experienced a primary cardiovascular event. A linear association with primary cardiovascular events was observed. Adjustment for cardiovascular risk factors explained about 50% of the excess risk and attenuated hazard ratios (95 confidence interval) for increased HbA1c to 1.14 (1.03-1.27), 1.17 (1.00-1.37) and 1.19 (1.04-1.37) for all-cause mortality, cardiovascular mortality and cardiovascular events, respectively. The six cohorts yielded inconsistent results for the association of very low HbA1c levels with the mortality outcomes and the pooled effect estimates were not statistically significant. In one cohort with a pronounced J-shaped association of HbA1c levels with all-cause and cardiovascular mortality (NHANES), the following confounders of the association of very low HbA1c levels with mortality outcomes were identified: race/ethnicity; alcohol consumption; BMI; as well as biomarkers of iron deficiency anemia and liver function. Associations for very low HbA1c levels lost statistical significance in this cohort after adjusting for these confounders.

CONCLUSIONS

A linear association of HbA1c levels with primary cardiovascular events was observed. For cardiovascular and all-cause mortality, the observed small effect sizes at both the lower and upper end of HbA1c distribution do not support the notion of a J-shaped association of HbA1c levels because a certain degree of residual confounding needs to be considered in the interpretation of the results.

B-vitamin levels and genetics of hyperhomocysteinemia are not associated with arterial stiffness

BACKGROUND AND AIMS

Hyperhomocysteinemia is associated with arterial stiffness, but underlying pathophysiological mechanisms explaining this association are to be revealed. This study was aimed to explore two potential pathways concerning the one-carbon metabolism. A potential causal effect of homocysteine was explored using a genetic risk score reflecting an individual's risk of having a long-term elevated plasma homocysteine level and also associations with B-vitamin levels were investigated.

METHODS AND RESULTS

Baseline cross-sectional data of the B-PROOF study were used. In the cardiovascular subgroup (n = 567, 56% male, age 72.6 ± 5.6 yrs) pulse wave velocity (PWV) was determined using applanation tonometry. Plasma concentrations of vitamin B12, folate, methylmalonic acid (MMA) and holo transcobalamin (holoTC) were assessed and the genetic risk score was based on 13 SNPs being associated with elevated plasma homocysteine. Associations were examined using multivariable linear regression analysis. B-vitamin levels were not associated with PWV. The genetic risk score was also not associated with PWV. However, the homocysteine-gene interaction was significant (p < 0.001) in the association of the genetic risk score and PWV. Participants with the lowest genetic risk of having long-term elevated homocysteine levels, but with higher measured homocysteine levels, had the highest PWV levels.

CONCLUSION

Homocysteine is unlikely to be causally related to arterial stiffness, because there was no association with genetic variants causing hyperhomocysteinemia, whereas non-genetically determined hyperhomocysteinemia was associated with arterial stiffness. Moreover, the association between homocysteine and arterial stiffness was not mediated by B-vitamins. Possibly, high plasma homocysteine levels reflect an unidentified factor, that causes increased arterial stiffness.

Prevention of the metabolic syndrome in IGT subjects in a lifestyle intervention: results from the SLIM study

BACKGROUND AND AIMS

The Study on Lifestyle intervention and Impaired glucose tolerance Maastricht (SLIM), a randomized controlled trial, directed at diet and physical activity in impaired glucose tolerant subjects was effective to improve glucose tolerance and prevent type 2 diabetes. The aim of this study was to determine the effects of the SLIM lifestyle intervention on the incidence and prevalence of the metabolic syndrome (MetS) during the active intervention and four years thereafter.

METHODS AND RESULTS

MetS was diagnosed according to the NCEP ATP III criteria. At baseline, 66.4% of all participants (n = 146, age 57 ± 7 years, BMI 29.7 ± 3.6, 51.3% female) fulfilled the criteria for MetS. No significant difference in MetS prevalence was observed between the intervention (63.9%) and control group (68.9%). At the end of active intervention (average duration 4.2 ± 2.0 years), prevalence of MetS was significantly lower in the intervention group (52.6%, n = 57) compared to the control group (74.6%, n = 59) (p = 0.014). Furthermore, in participants without MetS at baseline, cumulative incidence of MetS was 18.2% in the intervention group at the end of active intervention, compared to 73.7% in the control group (Log-rank test, p = 0.011). Four years after stopping active intervention, the reduced incidence of MetS was maintained (Log-rank test, p = 0.002).

CONCLUSION

In conclusion, a combined diet-and-exercise intervention to improve glucose tolerance, not only prevented type 2 diabetes, but also reduced the prevalence of MetS and prevented MetS development, showing the long-term impact of lifestyle intervention on cardiovascular risk reduction.

Design and cohort description of the InterAct Project: an examination of the interaction of genetic and lifestyle factors on the incidence of type 2 diabetes in the EPIC Study

AIMS/HYPOTHESIS

Studying gene-lifestyle interaction may help to identify lifestyle factors that modify genetic susceptibility and uncover genetic loci exerting important subgroup effects. Adequately powered studies with prospective, unbiased, standardised assessment of key behavioural factors for gene-lifestyle studies are lacking. This case-cohort study aims to investigate how genetic and potentially modifiable lifestyle and behavioural factors, particularly diet and physical activity, interact in their influence on the risk of developing type 2 diabetes.

METHODS

Incident cases of type 2 diabetes occurring in European Prospective Investigation into Cancer and Nutrition (EPIC) cohorts between 1991 and 2007 from eight of the ten EPIC countries were ascertained and verified. Prentice-weighted Cox regression and random-effects meta-analyses were used to investigate differences in diabetes incidence by age and sex.

RESULTS

A total of 12,403 verified incident cases of type 2 diabetes occurred during 3.99 million person-years of follow-up of 340,234 EPIC participants eligible for InterAct. We defined a centre-stratified subcohort of 16,154 individuals for comparative analyses. Individuals with incident diabetes who were randomly selected into the subcohort (n = 778) were included as cases in the analyses. All prevalent diabetes cases were excluded from the study. InterAct cases were followed-up for an average of 6.9 years; 49.7% were men. Mean baseline age and age at diagnosis were 55.6 and 62.5 years, mean BMI and waist circumference values were 29.4 kg/m(2) and 102.7 cm in men, and 30.1 kg/m(2) and 92.8 cm in women, respectively. Risk of type 2 diabetes increased linearly with age, with an overall HR of 1.56 (95% CI 1.48-1.64) for a 10 year age difference, adjusted for sex. A male excess in the risk of incident diabetes was consistently observed across all countries, with a pooled HR of 1.51 (95% CI 1.39-1.64), adjusted for age.

CONCLUSIONS/INTERPRETATION

InterAct is a large, well-powered, prospective study that will inform our understanding of the interplay between genes and lifestyle factors on the risk of type 2 diabetes development.

Cardiovascular risk factors and 10-year all-cause mortality in elderly European male populations; the FINE study. Finland, Italy, Netherlands, Elderly

BACKGROUND

This study aims to examine cardiovascular risk factors in relation to all-cause mortality in elderly populations of different European countries.

METHODS

Men aged 65--84 years from defined administrative areas were enrolled in Finland (rural areas of east and west Finland; n=716), in the Netherlands (the town of Zutphen; n=887), and in Italy (the rural areas of Crevalcore and Montegiorgio; n=682). Ten-year all-cause mortality was studied in relation to measurements taken at entry: age, systolic blood pressure, HDL- and non-HDL-cholesterol, body mass index, heart rate and smoking habits. Univariate and multivariate analyses were performed with all-cause mortality as the end-point.

RESULTS

Ten-year death rates from all causes were higher in Finland (574 per 1000), lower in the Netherlands (475 per 1000), and Italy (466 per 1000). Age, heart rate and smoking in all three countries were independently associated with 10-year all-cause mortality. Non-HDL-cholesterol was not related with all-cause mortality. The observed associations between HDL-cholesterol, systolic blood pressure, body mass index and all-cause mortality were dependent on the in- or exclusions of early death.

CONCLUSION

In these elderly men only age, smoking habits and heart rate were consistently associated with all-cause mortality.

Saturated fat, vitamin C and smoking predict long-term population all-cause mortality rates in the Seven Countries Study

BACKGROUND

The Seven Countries Study has shown that population mortality rates for various chronic diseases are related to diet and smoking. This paper addresses the associations between diet, smoking and 25-year all-cause mortality.

METHODS

Baseline surveys were carried out between 1958 and 1964 on 12,763 middle-aged men constituting 16 cohorts in seven countries. In 1987/88 equivalent food composites representing the average food intake of each cohort at baseline were collected and chemically analysed in one central laboratory. During 25 years of follow-up 5973 men died and age-adjusted population mortality rates were calculated for each cohort.

RESULTS

Multivariate linear regression analyses showed that the population intake of saturated fat and the prevalence of smoking were positively associated with population all-cause mortality rates. Population vitamin C intake was inversely associated with all-cause mortality. It was calculated that a reduction in saturated fat intake of 5% of energy, a 20 mg/d increase in vitamin C and a 10% decrease in the prevalence of smokers may decrease the 25-year all-cause population mortality rate by 12.4% (95% CI: 5.6, 19.4%) at an average population all-cause mortality rate of 45%.

CONCLUSION

At the population level saturated fat, vitamin C and cigarette smoking are important determinants of all-cause mortality.

Dietary pattern and 20 year mortality in elderly men in Finland, Italy, and The Netherlands: longitudinal cohort study

OBJECTIVE

To investigate the association of dietary pattern and mortality in international data.

DESIGN

Cohort study with 20 years' follow up of mortality.

SETTING

Five cohorts in Finland, the Netherlands, and Italy.

SUBJECTS

Population based random sample of 3045 men aged 50-70 years in 1970.

MAIN OUTCOME MEASURES

Food intake was estimated using a cross check dietary history. In this dietary survey method, the usual food consumption pattern in the 6-12 months is estimated. A healthy diet indicator was calculated for the dietary pattern, using the World Health Organisation's guidelines for the prevention of chronic diseases. Vital status was verified after 20 years of follow up, and death rates were calculated.

RESULTS

Dietary intake varied greatly in 1970 between the three countries. In Finland and the Netherlands the intake of saturated fatty acids and cholesterol was high and the intake of alcohol was low; in Italy the opposite was observed. In total 1796 men (59%) died during 20 years of follow up. The healthy diet indicator was inversely associated with mortality (P for trend < 0.05). After adjustment for age, smoking, and alcohol consumption, the relative risk in the group with the healthiest diet indicator compared with the group with the least healthy was 0.87 (95% confidence interval 0.77 to 0.98). Estimated relative risks were essentially similar within each country.

CONCLUSIONS

Dietary intake of men aged 50-70 is associated with a 20 year, all cause mortality in different cultures. The healthy diet indicator is useful in evaluating the relation of mortality to dietary patterns.

The validity and reliability of the Diabetes Health Profile (DHP) in NIDDM patients referred for insulin therapy

Recently, a new diabetes-specific questionnaire, the Diabetes Health Profile (DHP), has been developed to identify psychosocial dysfunctioning of insulin-requiring (NIDDM) and insulin-dependent diabetes mellitus (IDDM) patients. The DHP comprises three dimensions: psychological distress (PSY: 14 items), barriers to activity (BAR: 12 items) and disinhibited eating (EAT: five items). This study investigates the psychometric properties of the DHP in Dutch non-insulin-dependent diabetes mellitus (NIDDM) patients referred for insulin therapy. In addition, the relationship between patient characteristics and the DHP outcome was examined. The factor structure found was similar but not identical to former studies, but construct validity was supported by high correlations of our factor structure and the original factor outcome and Cronbach's alpha. The three factors explained 32% of the variance, supporting earlier findings. It was shown that Cronbach's alpha was satisfactory (0.72, 0.72 and 0.79). Convergent validity showed strong and significant correlations between the PSY/BAR dimensions and predicted corresponding scales of the RAND-36. However, the PSY/BAR dimensions also showed, although less strong, significant correlations with the non-corresponding RAND-36 scales. The EAT dimension showed only correlations with two of the RAND-36 dimensions, thus measuring a different trait. Regression analysis showed that older patients had less problems with items of the EAT dimension and that no difference was found between men and women, supporting earlier findings. The hyperglycaemic complaint "fatigue' gave a significantly lower score (more problems) on the PSY and BAR dimensions. Younger age, the presence of hypertension and retinopathy resulted in a significantly lower score on the EAT dimension. DHP outcome was not significantly influenced by duration of diabetes, HbA1c (indicator of glycemic control), serum total cholesterol, body mass index, chronic diabetes complications and co-morbidity. Overall, the psychometric properties were good considering the small and diverse sample, suggesting that the DHP is promising for use in NIDDM patients, although more study is necessary in a larger sample.

Short-term all-cause mortality and its determinants in elderly male populations in Finland, The Netherlands, and Italy: the FINE Study. Finland, Italy, Netherlands Elderly Study

BACKGROUND

This study aims at identifying determinants of all-cause mortality in elderly populations of different countries.

METHODS

Men ages 65-84 years from defined administrative areas were enrolled in Finland (rural areas of east and west Finland; N = 693), in the Netherlands (the town of Zutphen; N = 851), and in Italy (the rural areas of Crevalcore and Montegiorgio; N = 682). They were survivors of cohorts studies for 25 years within the Seven Countries Study with the addition of a subgroup of the same ages in the Netherlands.

RESULTS

Five-year death rates from all causes were higher in Finland (297 per 1000), intermediate in the Netherlands (231 per 1000), and lower in Italy (191 per 1000). Five-year all-cause mortality was studied in relation to measurements taken at entry (age, systolic and diastolic blood pressure, non-high-density lipoprotein (HDL) and HDL cholesterol, body mass index, heart rate, smoking habits, and presence of coronary heart disease manifestations). Univariate and multivariate analyses were performed (in the latter models, both linear and quadratic terms were used for most variables) with all-cause mortality as endpoint. Results suggested significant predictive power of age (direct relationship) and, in most cases, U-shaped relationships of risk factors to mortality. Non-HDL cholesterol showed significant relationships with mortality in Finland and the Netherlands, HDL cholesterol in all three countries, systolic blood pressure only in Finland, body mass index in Finland and the Netherlands, smoking habits only in Finland, and heart rate in none. Levels of risk factors associated with the lowest death rate in the pool of all countries were 183.3 mg/dl for non-HDL cholesterol, 59.8 for HDL cholesterol, 177.5 mm Hg for blood pressure, and 30.2 kg/m square for body mass index.

CONCLUSIONS

In these elderly men the association of traditional risk factors with all-cause mortality is reduced, U-shaped, or even inverted. This is probably due to selection due to previous mortality, to comorbidity, and to changes in homeostatic mechanisms.

Fluoride and sugar intake among adults and youth in Mauritius: preliminary results

The potential use of different vehicles for delivering fluoride to prevent dental caries has been discussed recently in Mauritius. Water fluoridation was found not to be feasible, and extending the fluoride tablet program would not be easy. Thus, sugar fluoridation as one possibility was considered. For these purposes, the average fluoride and sugar intake was estimated in Mauritius. The results are based on two studies--a Survey on Diet, Health and Lifestyle of Youth in Mauritius (1990) and the Mauritius Diet and Health Survey. Information was collected by trained interviewers using food-frequency and 24-hour-recall questionnaires. The daily total sugar intake, manufactured and natural, was found to be 62 g per day in young people and 50 g per day in adults. In the younger groups, daily frequencies of raw sugar, sweets, and biscuit (cookie) consumption were 1.5, 0.2, and 0.2 times a day, respectively. For adults, the mean daily frequency of consuming sugar-containing foods was 2.6 (SD = 1.3). The daily sucrose intake was rather high, representing about 10% of the daily energy intake. The fluoride levels of foods were calculated by use of Finnish and other available fluoride tables. The mean fluoride intakes per day were 0.64, 0.72, and 0.62 mg per day for 8-17-year-, 18-24-year-, and 30-64-year-old groups, respectively. The median fluoride intake for the oldest group was 0.62 mg/day. The estimated fluoride intake from food did not correspond with the proposed level for the prevention of caries (Murray, 1986) except for the 18-24-year-olds, where it might have been just above the lower recommended limit. However, further data based on analysis of the fluoride contents of Mauritian food samples, especially of whole daily diet, are needed.

[Prevalence of some cardiovascular risk factors in a sample of the aged population]

The distribution of some cardiovascular risk factors in a cohort of elderly population is reported. The study population consisted of 427 males aged 71-91, examined in 1991 and belonging to the Italian rural section of the Seven Countries Study on Cardiovascular Diseases. Systolic blood pressure shows an increasing trend with age, with mean levels greater than 160 mmHg in each quinquennium, while the prevalence of hypertension ranges between 60 and 75%. Other risk factors considered such as serum cholesterol, triglycerides, weight, height and smoking habit show decreasing levels with ageing. This trend is clear also for fasting glucose from the age group 76-80.